An alternating current (AC) lighting system refers to a system that directly drives a lighting load such as a light emitting diode (LED), an organic light emitting diode (OLED), or other light emitting devices or components using rectified AC line voltage from an AC power source. AC lighting systems eliminate the need of a power conversion unit that converts electrical power from an AC power source to a direct current (DC) power source. Due to their simple design and less components, AC lighting systems provide a low-cost solution for residential or commercial applications receiving and utilizing electrical power directly from an AC power source.
A surge refers to a dramatic increase of voltage for a short period of time (e.g., up to 50 microseconds). If a surge is high enough and lasts long enough, components can heat and burn. Surges can damage electronic circuits and shorten their service life. Surges can be classified as external or internal. While external surges (caused by storms and normal power company switching operations) are generally more severe, internal surges generally occur more frequently, for example, when equipment is cycling on and off. Surges can cause all types of problems, ranging from soft errors where information is scrambled in computing systems to gradual circuit deterioration resulting in premature failure and intermittent operation to outright destruction of circuits. Surges can over time wear out delicate circuits, causing intermittent problems and slowing down the operation of a system.
An AC direct step driver lighting system that is directly connected to an AC power source (e.g., 120/220 VAC) can be damaged by a short circuit or by an overload condition caused by a failure of components and/or circuits inside the AC direct step driver lighting system. In addition, a lightning surge or load switching transient that originates outside the AC direct step driver lighting system can create a voltage or current spike that can stress and damage components and circuits of the lighting system ultimately rendering the entire lighting system non-operational.